From EP 1 688 602 A1 a generic adjustment ring of a variable turbine geometry of an exhaust gas turbocharger is known, which in the contact region to a guide vane lever has an insert bush, in order to enlarge a contact surface to the link lever and thereby to increase the wear resistance.
From DE 10 2012 218 138 A1 an exhaust gas turbocharger with a variable turbine geometry is known, wherein the variable turbine geometry has guide vanes mounted rotatably in a vane bearing ring, which guide vanes are adjustable by means of an adjustment element. The adjustment element itself is configured here as a thin sheet component and has a smaller diameter than the vane bearing ring.
From WO 2009/115437 A1 a vane grille arrangement is known of an exhaust gas turbocharger with variable turbine geometry and with at least one carrier ring, formed from at least one sheet metal part, for the bearing of guide vanes.
Generally, in an exhaust gas turbocharger with variable turbine geometry, an adjustment ring is used for adjusting the guide vanes, which adjustment ring is connected on the one hand to a guide vane lever and on the other hand to the adjustment levers of the individual guide vanes. At the contact points to the guide vane lever and to the individual adjustment levers of the guide vanes, however, an increased wear can occur owing to relative movements and great contact forces. In order to be able to keep this wear within limits at the engagement points of the adjustment ring, often both the guide vane lever and also the individual adjustment levers and/or the adjustment ring are provided with a wear-resistant coating, for example with a nitriding layer. In order, furthermore, to be able to reduce the surface pressure, often also the thickness of the adjustment ring is increased as a whole or only locally in the region of the recesses which are in contact with the adjustment levers or respectively with the guide vane lever.
A disadvantage in the stamped adjustment rings with comparatively great thickness, known from the prior art, however, is that these require a high pressing force for production, particularly in the case of components greater than 6 mm, and have a potentially higher risk with regard to dimensional accuracy. Furthermore, in the case of stamped parts with a component thickness increase in the millimetre range, only a proportionately higher smooth cut proportion and therefore only a somewhat greater contact height occurs compared to the overall thickness of the adjustment ring. Alternatively here of course the production of such an adjustment ring as a cast part is also conceivable, wherein here, however, a complex and also cost-intensive post-processing is necessary, in order to be able to achieve the necessary tolerances for fulfilling the function over the lifespan.